Re: Understanding my pool system. Close suction from drain p
If you have one main drain and one skimmer, and you have two pipes coming up in front of the pump, then I would think that one of the pipes comes from the skimmer and one of the pipes comes from the main drain.
Normally, each pipe has its own valve so that you can turn either off, or on, independently. Only one of the pipes has a valve. I am guessing that the one with the valve is the main drain.
If you look into the second hole in the skimmer, can you see how deep it goes? Is it plugged? I suppose that it could go to the main drain, but then what are the two lines coming up in front of the pump?
Since you have the float valve, then I would think that there has to be a second source of water, either an equalizer or main drain. Perhaps the second hole "T"s into the main drain line and the main drain also goes directly to the pump.
I don't know what the 1/2 inch hole is, it might be a fill line, drain line or equalizer?
Can you feel if there is suction on the main drain when the valve is open or closed? (Don't try to do this is you're not sure that it can be done safely.)
How many returns are there?
Can you post a picture of the pool?